Experimental and mechanistic study of fracturing fluid injury in ultra-low permeability volcanic reservoirs
Guanidine gel and polymer fracturing fluid systems have different injury characteristics for ul-tra-low permeability volcanic reservoirs.Guanidine gel fracturing fluid has a high content of residue after breaking the gel,which is easy to block sand-filled cracks and reduce the capacity of fracture inflow.Poly-mer fracturing fluids are characterised by thorough gel breakage and low residue content.The mineral composition and specific surface area of five groups of volcanic rock samples from a well area in the Chaganhua region taken from 4 045～4 669 m were characterised by X-ray diffraction and BET tech-niques.Quantitative evaluation of fracturing fluid damage to reservoir cores by core adsorption experi-ments.Zeta potential,contact angle,infrared spectroscopy and SEM before and after testing the injury were used to analyse the mechanism of fracturing fluid injury to the reservoir.Only physical adsorption of both fracturing fluids occurred on the core powder surface,with guanidine gum adsorption being 33.6%higher than polymer.The contact between guanidine gum and core powder causes the absolute value of Zeta po-tential to become smaller,and the system is unstable and easy to be adsorbed and retained on the core surface.Increased hydrophobicity leads to larger contact angles.
万方数据
